New SOP for Preparation of Calibration Certificates
Calibration certificates are the visible outputs that convey all the information pertaining to a calibration performed in the lab. They provide important information to help show proof of the calibration and to give the instrument’s owner confidence that the device was calibrated correctly. They are a critical part of your business and essential to ISO/IEC 17025 accreditation, so you want to make sure that you are following best practices.
2017 brought the ISO/IEC 17025 revision and subsequently the NIST has revised it’s Standard Operating Procedure (SOP) for the Preparation of Calibration Certificates to comply with the revised Reporting of Results, section 7.8. Have you taken the time to review your calibration certificates to see if they meet the new standards?
Content of Calibration Certificates
There are multiple additions in the updated SOP. Some are minor and may already be included on your certs, such as the date of issue of the report or clear identification when the results are from external providers, but others are likely going to require a more major change in your calibration certificates. For example, on reports that include a statement of conformity to a specification or standard, the laboratory must now document the decision rule it employs, taking into account the level of risk associated with the decision rule will have on reporting false positive or negative results, and apply the decision rule. 😳
Each calibration certificate shall contain the information listed below. The results can be reported in a simplified manner when agreed upon with the customer; however, any information not reported to the customer must be maintained by the laboratory and readily available.
The full details of the content required on the Calibration Certificates as outlined in the SOP are below. Use our handy printable checklist as an assessment tool for your calibration certificates.
- Title (e.g., “Calibration Certificate”).
- Name and address of the laboratory where the calibration is performed (e.g., permanent facility), including any alternative location were a calibration is performed (e.g., temporary, mobile, or alternative facility).
- Unique identification that all calibration certificate components are recognized, and an identification on each page to ensure that the page is recognized as part of the complete document, and a clear identification of the end of the certificate. A unique calibration number and page X of Y formatting are frequently used to uniquely identify the components of a calibration certificate.
- Customer name and contact information.
- Method used –Cite the Standard Operating Procedure (SOP), including the full title or description and the version date. In the absence of a nationally or internationally published SOP, a brief but informative description of the methodology shall be included. When a customer approves of an addition, deviation, or exclusion from the published method, these departures shall also be included
- Unambiguous identification and description of the calibration artifact, and when necessary, the condition of the item. Serial numbers are assigned to items by the customer, laboratory, or manufacturer to facilitate the internal control of the item during the calibration process and subsequent use by the customer. Unique identification is verified when an item is submitted to the laboratory for calibration.
- Date(s) of:
- Calibration item receipt;
- Sampling, where critical to the validity and application of the results;
- Calibration or laboratory activity performance; and
- Certificate issuance.
- Cite the sampling plan and methods used. Uniquely identify the items sampled. Include the:
- The date and location of sampling;
- Environmental conditions during sampling that affect the interpretation of results; and
- Information related to the measurement uncertainty, where relevant.
- Calibration results and corresponding units of measurement are clearly organized in a tabular or other convenient format. When a calibration item has been repaired or adjusted, the calibration results before and after repair or adjustment shall be reported. measurement units reported are typically related to the nominal value of the calibration item. Measurement units may be selected to reflect an industry practice or a customer request.
- A statement of the measurement uncertainty, and corresponding measurement unit, coverage factor, and estimated confidence interval shall accompany the measurement result. The measurement uncertainty is reported in the same measurement units as the measurement result (e.g., multiple or submultiple). Special care shall be used when the coverage factor is not consistent for all calibrated items. The results table should be formatted clearly identify individual coverage factors when variations exist (e.g., an additional column containing the corresponding coverage factors). When appropriate, significant uncertainty components and the rationale for their inclusion are included. Note: the use of standard industry practices or reporting units based on customer requests is permitted.
- Environmental or other conditions under which the calibrations were made that influence the measurement results.
- Clearly identify the person(s) performing the calibration and authorizing calibration certificate by stating their corresponding name, title, and signature. Each authorized signatory accepts responsibility for the technical accuracy and validity of the reported results.
- A statement to the effect that the results relate only to the items calibrated or sampled.
- A statement identifying how the measurements are metrological traceability (e.g., the laboratory establishes metrological traceability to the International System of Units (SI) and is recognized by NIST OWM). The inclusion of supplemental supporting information may be requested by the customer.
- When statement of compliance or non-compliance with requirements and/or specifications (e.g., a conformity assessment), where relevant. Compliance refers to an assessment of all criteria of a referenced documentary standard and not a limited assessment of a portion or specific clauses (e.g., compliance to all specifications versus only the tolerance specification). When a statement of conformity is made, the laboratory must clearly identify to which results the statement of conformity applies (e.g., all results or a specific portion of the results), which specifications, standards or parts thereof are met or not met, and the decision rule applied (unless the decision rule is inherent in the specification or documentary standard). When a statement of conformity to a specification or documentary standard is made, the laboratory shall document the decision rule applied, take into account the level of risk associated with the decision rule employed (such as false accept, false reject, and statistical assumptions), and apply the decision rule. Where decision rules regarding uncertainties and tolerances are not part of the documentary standard, decision rules will be agreed to by the customer and reported on the calibration certificate.
- Opinions and interpretations, where appropriate and needed, shall be based on the measurement results, clearly stated, and identified as such. Only technically competent laboratory personnel are permitted to express opinions and interpretations (e.g., an authorized signatory). When opinions and interpretations are directly communicated and discussed with the customer, a record of the conversation shall be documented and retained.
- Results from external providers shall be clearly identified.
- Additional information which may be required by specifications, specific methods, customers, or groups of customers.
- To ensure parts of the calibration certificate results are not taken out of context, a statement specifying that the calibration certificate shall not be reproduced except in full, without written approval of the laboratory may be included.
- A calibration certificate or calibration label shall not include any recommended calibration interval, except when required for legal applications or where requested and agreed to by the customer.
IndySoft has been supporting the software needs of Enterprise Calibration and Commercial Labs for twenty years. If you would like information on how IndySoft can assist you with your Calibration Certificates, please contact sales@IndySoft.com. Click here: Recommended Standard Operating Procedure for Calibration Certificate Preparation to view the entire SOP.